Light-emitting element and the manufacturing method thereof

ABSTRACT

A light-emitting element includes a light-emitting stack includes: a first semiconductor layer; an active layer formed on the first semiconductor layer; and a second semiconductor layer formed on the active layer; a recess structure formed through the second semiconductor layer, the active layer, and extended in the first semiconductor layer, wherein the first semiconductor layer includes a contact region defined by the recess structure; a first electrode structure including a first contact portion on the contact region of the first semiconductor layer, and a second contact portion laterally extended from the first contact portion into the first semiconductor layer; and a dielectric layer formed on side surfaces of the second semiconductor layer and the active layer to insulate the second semiconductor layer and the active layer from the first contact portion.

TECHNICAL FIELD

The application relates to a light-emitting element and themanufacturing method thereof.

DESCRIPTION OF BACKGROUND ART

The features of the light emitting diode (LED) mainly include the smallsize, high efficiency, long life, quick reaction, high reliability, andfine color. So far, the LED has been applied to electronic devices,vehicles, signboards, traffic signs, and many other applications. Alongwith the launch of the full-color LED, LED has gradually replacedtraditional lighting apparatus such as fluorescent lights andincandescent lamps.

Referring to FIG. 1, a light-emitting device 1 includes a p-typeelectrode and an n-type electrode. The p-type electrode includes p-typebonding pads 14, two first armed electrodes 14 a extending from thep-type bonding pad 14, and second armed electrodes 14 b interposedbetween two first armed electrodes 14 a. The current is injected fromthe p-type bonding pad 14 and spread by the armed electrodes. The n-typeelectrode includes n-type bonding pads 15, third armed electrodes 15 a,and fourth armed electrodes 15 b. The current is injected from thep-type electrode, moves to the light-emitting region of thelight-emitting device 1, and then flows to and out of the n-typeelectrode. The p-type armed electrodes 14 a, 14 b and the n-type armedelectrodes 15 a, 15 b are interdigitated between each other.

SUMMARY OF THE DISCLOSURE

A light-emitting element includes a light-emitting stack including: afirst semiconductor layer; an active layer formed on the firstsemiconductor layer; and a second semiconductor layer formed on theactive layer; a recess structure formed through the second semiconductorlayer, the active layer, and extended in the first semiconductor layer,wherein the first semiconductor layer includes a contact region definedby the recess structure; a first electrode structure including a firstcontact portion on the contact region of the first semiconductor layer,and a second contact portion laterally extended from the first contactportion into the first semiconductor layer; and a dielectric layerformed on side surfaces of the second semiconductor layer and the activelayer to insulate the second semiconductor layer and the active layerfrom the first contact portion.

A manufacturing method of a light-emitting element including steps of:providing a light-emitting element including a substrate; and alight-emitting stack including a first semiconductor layer, an activelayer formed on the first semiconductor layer, and a secondsemiconductor layer formed on the active layer; forming at least arecess structure through the second semiconductor layer and the activelayer, and extended into first semiconductor layer; forming a dielectriclayer on the second semiconductor layer and the active layer in therecess structure; forming an embedded hole laterally extended from therecess structure into the first semiconductor layer; and forming a firstelectrode structure on the first semiconductor layer via the recessstructure and the embedded hole.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view of a conventional light-emitting device.

FIG. 2A is a cross-sectional view of a light-emitting element of a firstembodiment of the present application.

FIG. 2B is a top view of a light-emitting element of a first embodimentof the present application.

FIG. 3A to FIG. 3F show a manufacturing method of a light-emittingelement of a first embodiment of the present application.

FIG. 4 is a cross-sectional of a light-emitting element of a secondembodiment of the present application.

FIG. 5A to FIG. 5E show a manufacturing method of a light-emittingelement of a second embodiment of the present application.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

As shown in FIG. 2A, a light-emitting element 200 of a first embodimentof the present application includes: a light-emitting stack 202including a first semiconductor layer 204, an active layer 206 formed onthe first semiconductor layer 204, and a second semiconductor layer 208formed on the active layer 206; a recess structure 210 formed throughthe second semiconductor layer 208, the active layer 206, and extendedin the first semiconductor layer 204, wherein the first semiconductorlayer 204 includes a contact region 212 defined by the recess structure210; a first electrode structure 214 including a first contact portion214 a on the contact region 212 of the first semiconductor layer 204,and an second contact portion 214 b laterally extended from the firstcontact portion 214 a into the first semiconductor layer 204, wherein apartial portion of the second contact portion 214 b is lower than thecontact region 212; and a dielectric layer 216 formed on the uppersurface of second semiconductor layer 208 and side surfaces of thesecond semiconductor layer 208 and the active layer 206 so the secondsemiconductor layer 208 and the active layer 206 is insulated from thefirst contact portion 214 a. The thickness h of the first contactportion 214 a, which is defined by the distance from the contact region212 to the top of the first contact portion 214 a can be thicker than3000 Å, or the top of the first contact portion 214 a can reach a levelbetween the active layer 206 and the upper surface of the secondsemiconductor layer 208. An etching stop layer 205 can be formed betweenthe first electrode structure 214 and the contact region 212 of thefirst semiconductor layer 204. The etching stop layer 205 can be a filmmade of one material selected from the group consisting of Ti, Cr, Cu,Mo, Ni, Au, Ag, Pt, W, Al, Fe, Co, Pd, Sn, and Zn, or a metal alloythereof. The light-emitting element 200 further includes a substrate 201for carrying the light-emitting stack 202, wherein the material ofsubstrate 201 can be electrically insulative such as sapphire, diamond,glass, quartz, acryl, ZnO, or AlN. The substrate 201 can also be aconductive material such as GaN, GaAs, or Si with an insulative bondinglayer formed between the substrate 201 and the light-emitting stack 202.Further referring to FIG. 2B, the first electrode 214 includes a bondingelectrode 217 and at least an extension electrode 218 extended from thebonding electrode 217, and the first contact portion 214 a in FIG. 2Acan be the bonding electrode 217 and/or the extension electrode 218. Thesecond contact portion 214 b can be extended from the extensionelectrode 218, the bonding electrode 217, or both of the extensionelectrode 218 and the bonding electrode 217. The conventionallight-emitting element usually has upper and lower electrode structureson the same side, and an extension electrode of the lower electrodestructure is located in a recess structure. The width of the extensionelectrode must be smaller than that of the recess structure forinsulation purpose, but the electrical contact between the extensionelectrode and the semiconductor layer is therefore poor. In the presentembodiment, the extension electrode 218 can have good electrical contactwith the first semiconductor layer 204 by extending the second contactportion 214 b into the first semiconductor 204. Moreover, the secondcontact portion 214 b is under the active layer 206 and does not blockthe light emitted from the active layer 206. Furthermore, the width ofthe extension electrode 218 can approach to the width of the recessstructure 210 to be wider than that of the conventional light-emittingelement, and the electrical resistance of the extension electrode 218can be lowered. In addition, the light-emitting element 200 can furtherinclude a second electrode structure 220 including a bonding electrode222 and an extension electrode 224 extended from the bonding electrode222.

The material of the light-emitting stack 202 can be III-V groupsemiconductor materials containing Al, Ga, In, N, P or As elements, suchas GaN series, AlGaInP series or GaAs series. The first semiconductorlayer 204 can be n type, and the second semiconductor layer 208 can be ptype, or the polarity of them can be exchanged. The manufacturing methodof the light-emitting element 200 can include forming the recessstructure 210 through the second semiconductor layer 208, the activelayer 206, and extended into the first semiconductor layer 204, andduring the process of forming the recess structure 210, the dielectriclayer 216 covers the second semiconductor layer 208 and the active layer206 in the recess structure 210; forming an embedded hole 207 laterallyextended from the recess structure 210 into the first semiconductorlayer 204; and forming the first electrode structure 214 on the firstsemiconductor layer 204 via the recess structure 210 and the embeddedhole 207. The details of the process for producing the first electrodestructure 214 are described as follows.

Referring to FIG. 3A to FIG. 3D, a manufacturing method of alight-emitting element of the first embodiment of the presentapplication is disclosed. As shown in FIG. 3A, a light-emitting element200 includes a substrate 201; and a light-emitting stack 202 formed onthe substrate 201 and including a first semiconductor layer 204, anactive layer 206 formed on the first semiconductor layer 204, and asecond semiconductor layer 208 formed on the active layer 206. Aninitial recess structure 203 is formed through the second semiconductorlayer 208 and the active layer 206 to expose the first semiconductorlayer 204 by etching process such as wet etching. As shown in FIG. 3B, adielectric layer 216 covers the second semiconductor layer 208 and theinitial recess structure 203, wherein the dielectric layer 216 can beSiN_(x) or SiO₂ formed by deposition, or silicone resin, BCB, epoxy,polyimide or PFCB formed by coating. As shown in FIG. 3C, the dielectriclayer 216 on the bottom surface of the initial recess structure 203 isremoved by a wet etching process, and then a recess structure 210 isformed by extending the initial recess structure 203 into the firstsemiconductor layer 204 by another wet etching process. As shown in FIG.3D, an etching stop layer 205 can be optionally formed on the bottomsurface of the recess structure 210. As shown in FIG. 3E, an embeddedhole 207 is laterally extended from the recess structure 210 by etchingprocess such as wet etching, and the bottom surface of the recessstructure 210 is not etched because of the etching stop layer 205thereon. The embedded hole 207 can be also vertically extended in thefirst semiconductor layer 204 by controlling the etching period. Asshown in FIG. 3F, forming a first electrode structure 214 includingmetal or metal alloy in the embedded hole 207 and, the recess structure210 by plating process such as chemical plating (electroless plating) orelectro plating. Referring to FIG. 2B, the second electrode structure220 can be formed at the same time by covering a mask (not shown) on thelight-emitting element 200 to expose a predetermined plating region ofthe first semiconductor layer 204 and the second semiconductor layer208, and then performing the plating, and the mask can be removed afterforming the first electrode structure 214 and the second electrodestructure 220.

As shown in FIG. 4, a light-emitting element 300 of a second embodimentof the present application includes a light-emitting stack 302 includinga first semiconductor layer 304, an active layer 306 formed on the firstsemiconductor layer 304, and a second semiconductor layer 308 formed onthe active layer 306; a recess structure 310 formed through the secondsemiconductor layer 308, the active layer 306, and extended into thefirst semiconductor layer 304, wherein the first semiconductor layer 304includes a contact region 312 defined by the recess structure 310,wherein the contact region 312 includes a first section 312 a, and asecond section 312 b laterally extended from the first section 312 ainto the first semiconductor layer 304; a first electrode structure 314including a first contact portion 314 a on the first section 312 a ofthe first semiconductor layer 304, and a second contact portion 314 blaterally extended from the first contact portion 314 a into the firstsemiconductor layer 304 along the second region 312 b of the contactregion 312; and a dielectric layer 316 formed on the upper surface ofthe second semiconductor layer 308 and side surfaces of on the secondsemiconductor layer 308 and the active layer 306 so the secondsemiconductor layer 308 and the active layer 306 is insulated from thefirst contact portion 314 a of the first electrode structure 314. Thedifference between the first embodiment and the present embodiment isthat the first contact portion 314 a is directly in contact with thecontact region 312 of the first semiconductor layer 304, and the recessstructure 310 is deeper than that of the first embodiment. The contactregion 312 defined by the recess structure 310 is an arc surface.

Referring to FIG. 5A to FIG. 5E, a manufacturing method of alight-emitting element of the second embodiment of the presentapplication is disclosed. As shown in FIG. 5A, a light-emitting element300 includes a substrate 301; and a light-emitting stack 302 including afirst semiconductor layer 304, an active layer 306 formed on the firstsemiconductor layer 304, and a second semiconductor layer 308 formed onthe active layer 306. An initial recess structure 303 is formed throughthe second semiconductor layer 308 and the active layer 306 to exposethe first semiconductor layer 304 by etching process such as wetetching. As shown in FIG. 5B, a dielectric layer 316 conformably coversthe surface of the second semiconductor layer 308 and the initial recessstructure 303, wherein the dielectric layer 316 can be such as SiN_(x)or SiO₂ formed by deposition, or silicone resin, BCB, epoxy, polyimideor PFCB formed by coating. As shown in FIG. 5C, the dielectric layer 316on the bottom surface of the initial recess structure 303 is removed bywet etching process, and then a recess structure 310 is formed byextending the initial recess structure 303 into the first semiconductorlayer 304 by another wet etching process. As shown in FIG. 5D, a chamber307 is laterally and vertically extended from the recess structure 310by etching process such as wet etching. As shown in FIG. 5E, forming afirst electrode structure 314 including metal or metal alloy in thechamber 307 and the recess structure 310 by plating process such aschemical plating (electroless plating) or electro plating.

Although the present application has been explained above, it is not thelimitation of the range, the sequence in practice, the material inpractice, or the method in practice. Any modification or decoration forpresent application is not detached from the spirit and the range ofsuch.

What is claimed is:
 1. A light-emitting element comprising: alight-emitting stack comprising a top surface; a recess structurepenetrating the top surface, and comprising a first bottom surface and afirst side surface; a first electrode structure comprising a secondbottom surface electrically connected to the first bottom surface, and asecond side surface facing the first side surface; and a dielectriclayer formed between the first side surface and the second side surface.2. The light-emitting element according to claim 1, wherein thelight-emitting stack further comprises: a first semiconductor layerfacing to the first bottom surface and having a thickness; an activelayer formed on the first semiconductor layer; and a secondsemiconductor layer formed on the active layer.
 3. The light-emittingelement according to claim 2, wherein the recess structure has a depthless than the thickness of the first semiconductor layer.
 4. Thelight-emitting element according to claim 3, wherein the first electrodestructure comprises a contact portion laterally extended into the firstsemiconductor layer.
 5. The light-emitting element according to claim 2,wherein the first side surface is connected to the second semiconductorlayer, the active layer, and a partial thickness of the firstsemiconductor.
 6. The light-emitting element according to claim 1,wherein the first electrode structure comprises a top end higher thanthe active layer and lower than the top surface.
 7. The light-emittingelement according to claim 4, wherein the first electrode structurecomprises a bonding electrode and an extension electrode extended fromthe bonding electrode, and the contact portion is extended from theextension electrode.
 8. The light-emitting element according to claim 4,wherein the first electrode structure comprises a bonding electrode andan extension electrode extended from the bonding electrode, and thecontact portion is extended from the bonding electrode.
 9. Thelight-emitting element according to claim 4, wherein the first electrodestructure comprises a bonding electrode and an extension electrodeextended from the bonding electrode, and the contact portion is extendedfrom the bonding electrode and the extension electrode.
 10. Thelight-emitting element according to claim 1, further comprising an metallayer formed between the second bottom surface of the first electrodestructure and the first bottom surface of the recess structure.
 11. Thelight-emitting element according to claim 2, further comprising a secondelectrode structure formed on the second semiconductor layer.
 12. Thelight-emitting element according to claim 4, wherein the contact portionis under the active layer.
 13. The light-emitting element according toclaim 2, wherein the second bottom surface of the first electrodestructure is directly connected to the first semiconductor layer. 14.The light-emitting element according to claim 13, wherein the firstbottom surface comprises an arc surface.